Casey Luber Seiden MS, RD

The Ketogenic Diet: does it work or is it the worst?

You’re two weeks into the New Year- have you checked in with yourself? For those of you who set goals or intentions, how are they going for you? If you chose a Word of the Year, have you seen any rewards from adopting this outlook yet? Mine is confidence, and I can say that I am slowly starting to approach business-related goings-on with an attitude filled with more of the Big C, but I know I’ve got an entire year to fully grow into it- thank goodness!

Today is Martin Luther King Day and so with many people off work, myself included, I noticed the bump in activity while running around Central Park this morning. The gyms, fitness clubs, and diet websites were no doubt getting lots of traffic too as resolutioners hang on to their health focused goals while we approach the mid-way point of “Diet Month”. As a dietitian, who always gets questions about what diet to go on in the New Year (my answer is usually “no diet”), I took some time today to read up on what diets were “hot” and which were “not”- but are still adopted by many- this year.

Does this surprise you?

Let’s compare the Best and Worst:

The DASH diet primarily aims to prevent and lower high blood pressure, while helping your waistline at the same time. There is no tracking or counting involved, rather you eat recommended foods such as fruits, vegetables, whole grains, lean proteins, and low-fat dairy while limiting saturated fats, tropical oils, and sugar-sweetened beverages and sweets. Sounds pretty easy and delicious, right? It was ranked within the top 6 places for the following categories: best overall diet, weight loss, diabetes, healthy eating, heart healthy, and easiest diet to follow.

The Keto, or Ketogenic, Diet is infamously promoted as a weight loss diet through fat-burning, and also touts other benefits such as increased satiety and enhanced mood and mental focus. This diet relies almost exclusively on foods high in fat, moderate consumption of protein, and a very small amount of carbohydrates- only 20 grams, or the equivalent to 1 large slice of bread. The idea is to put your body in a state of ketosis, whereby you break down dietary and stored fat into substances called ketones, which can be used for energy, rather than using glycogen (stored carbohydrates) and glucose (sugar from food and the brain’s prefered fuel source). This diet was ranked among the middle of the pack for fast weight loss, but at the bottom of the list for overall, heart health, and easy to follow.

If you couldn’t already tell, I’m not a fan of the latter diet.

Any style of eating that asks you to restrict essentially an entire food group will always be hard to stick to and only leads to a cycle of deprivation and overconsumption again and again without attaining your healthy weight goals.

I still do stand firmly in the “No-Keto” camp for long-term weight maintenance and eating style satisfaction, but when I came across this research brief headline I was intrigued:

Keto for diabetes?

Since a ketogenic diet is limited (cough, very, cough) in carbohydrates this would make sense for someone with high blood sugar, which can be made more difficult to control when consuming large portions of foods high in simple and complex carbs. Restrict carbs, gain better blood sugar control- sounds simple enough.

So, I took a look at the study, as all evidence-based RDs do. The study was a randomized controlled trial that grouped 50 people into two diet groups: an ad libitum, very low-carb/keto diet (20-50 grams of carbohydrate, excluding fiber, per day), and a moderate-carb (45-50% of total daily calories), calorie-restricted (500 kcal less than calculated needs), low-fat diet group. Both groups attended nutrition classes, were taught about the importance of sleep and exercise, and were instructed and encouraged to practice mindful eating strategies to promote behavioral adherence.

Here’s what happened after 12 months:

Diet: compared to the moderate group, the low-carb group reported consuming fewer non-fiber grams of carbohydrates (6 and 12 months), more grams of fat (6 and 12 months), and more grams of protein (12 months), but not a different number of calories per day

Hemoglobin A1c (average measure of glucose control): participants in the low-carb group reduced their HbA1c levels more than participants in moderate group, a significant number of which dropped below 6.5% (the diagnostic criteria for diabetes)

Weight: at 12 months, participants in the low-carb group lost more weight and lowered their BMI more than participants in the moderate group

Lipids: at 6 months, LDL (“bad”) cholesterol increased more in the low-carb group compared to the moderate group, although at 12 months the groups no longer significantly differed

The researchers- who work for various universities in California, and only one of whom discloses a conflict in that he is a paid member of the Atkins (low-carb, high fat) Scientific Advisory Board- felt their study had good retention (only two people dropped out from the low-carb group, and 3 from the moderate group) and dietary adherence rates due in part to the fact that they trained the participants in positive affect and mindful eating strategies.

What do I see as the downfalls?

It is a very small sample size, which demonstrates that it might not be easily translateable to the larger population. Also, the study was limited to patients not using insulin. When having to inject insulin there is a a greater risk of hypoglycemia, or low blood sugar, and so consuming a sufficient, consistent amount of carbohydrates throughout the day is not only more sensible, but safer, for these persons with diabetes. I struggle to see how 20, or even 30, grams of carbohydrates would be enough for them, and also allow them 10-15 grams of “emergency” carbohydrate should their blood suagr drop dangerously low and they need to treat it with a juice or candy. The researchers in the study make no mention of hypoglycemic events, only that no one experienced diabetic ketoacidosis, which is a complication from having very high levels of glucose in the blood and is very unlikely to have happened when only consuming 20-50 grams of carbs per day.

My take-away from the research, and my daily experience with patients with diabetes, is that yes, limiting overall carbohydrate consumption can be incredibly beneficial for diabetes control, but

we can’t really call what the intervention group followed a “keto” diet and so we shouldn’t promote it as such.

I believe that practicing balance and finding satisfaction in your eating pattern is just as important. If including some sweet potatoes, quinoa, and oatmeal in your day helps maintain glycemic stability AND you enjoy this way of eating enough to maintain it long term, then I believe we’ve found the real secret to managing diabetes for life.